At Kmart, Sears, Toys R Us and Walmart, Black Friday starts at 8 p.m. on Thanksgiving. Target opens its doors at 9 p.m. on Thursday.

But wait, there's more.

"Instead of having all the door busters available as soon as the doors open, both Sears and Walmart are spreading the doorbusters out," says Edgar Dworsky, who runs the website ConsumerWorld.org.

"So at 8 p.m. certain doorbusters will be available. Then at 10 p.m. other doorbusters will be available. And then at 5 a.m. the next morning a third group of doorbusters will be available and this varies from chain to chain."

To make sure you don't get in line at the wrong time, you need to carefully read the circulars to make sure you know what time that doorbuster deal begins.

Remember, very few of the items on sale for Black Friday are truly doorbusters. And those are normally limited to just a few per store.